Stenciling



. Patented Feb. 15,1927.

UNITED STATES- PATENT OFFICE.

SYDNEY W. FUERTH, OF NEWARK, NEW JERSEY, ASSTGNOE TO UNDERWOOD TYPE- WRITER 'COMPANY.QF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

STENGILING.

Application filed April 16, 1924. Serial No. 706,802.

This invention relates generally to Wax sheets commonly used for typewritmg stencils, for. examplefthose disclosed in U.

S. Patent No. 995,780, dated June 20,1911,

to William G. Fuerth- An open-mesh tissue sheet (usually Japanese dental paper or yoshino) is saturated with parafiin, which is usually compounded with other mineral and vegetable waxes, and a shortening. In" the -typewriting machine this is backed by a soft porous sheet, upon which is deposited the wax which is forced out from the fibres I of the stencil sheet by the types.

A wax stencil, however, is fragile and short-lived, so that only about three hundred satisfactory copies can be made therefrom in an ordinary rotary duplicating or stenciling machine. One of the main objects of.

or the like, instead of wax, for coating the stencil sheet, and it is found necessary to wet the glue compound prior to typewriting thereon, and the wet sticky substance proves to be a serious objection in the typewriting machine. After typing, the sheet must be dried before making stencil copies. In PatentNo. 1,196,098 granted to me August 29, 1916, the interstices of the yoshino paper are filled up with a long-wearing preparation of shellac suitably softened and adapted for typewriter stenciling use, without incurring the necessity of wetting the sheet preparatory preparatory wetting. An object of the,

to typing thereon; but the present improvements aim to retain the advantages of the well known wax stencil sheets while overcoming their defects; for example, to prolong the life and increase the efliciency of the wax sheet by means which permit the retention of the valuable characteristic that a waxsheet can be typed without the need of a present invention therefore is to produce an inexpensive dry stencil sheet from which a large number of copies'can be made.

Other features and advantages will here.- inafter appear. The accompanying drawing shows dia grammatically a' varnished wax sheet embodying thepresent improvements, together with its softened porous backing sheet, and

also 1 the usual manila paper backing under said porous sheet.

, Inrcarrying out the'present improvements 1n one manner, a stencil sheet I is prepared with wax according toany preferred formula, as, for example, the formula set forth in said Patent 995,780. The Wax coating material 2 may be in the following proportions: 35 pounds of paraffin of 120 melting point, 35 pounds of ceresine, 5 pounds of lard for shortening, and 2' pounds ofjapan Wax for binding. In summer the lard may be reduced to 4 This is the well known Underwood wax sheet, although the invention will apply to other kinds of Wax papers for typewriter and other stenciling, and also for other purposes.

To the wax sheet there is applied, according to the present improvements, a dressing 3, preferably on one side only of the sheet. For this purpose there is used a preparation consisting of shellac varnish (6 bleached white shellac to one gal on of denatured alcohol, or Columbian spirits). The varnish is known to thetrade as 6- pound shellac varnish, and is of considerably less specific gravity than glycerin. To

ounds of this is added four volumes (by weight) of denatured alcohol, in which is dissolved a softener for the shellac dressing, in the form of Turkey-red oil, or sulphonated-castor oil, which may be in the proportion of 6 per cent by weight to the entire foregoing mixture. Then said previously prepared wax stencil sheet is floated upon' this solution, to

the end that a'thin dressing or coating of shellac may be applied upon the wax coating of the stencil sheet; the sheet being floated with its wax-coated side down. All of the mixtures may be combined at a temperature of about 60 or 70, or ordinary laboratory temperature,'and the bath may be kept at asimilar temperature. After being floated upon the mixture, the sheet is suspended for a suitable time, say half an hour, to permit the evaporation of theexcess alcohol, and it is then ready for use.

The shellac sticks to the wax properly, and forms a permanent dressing and is very adherent, which is an advantage in the loop letters and otherwise. The'shellac coating is not, however, irremovable. To adapt the adherent but hard or refractory and brittle shellac varnish 'to the soft wax coat of the sheet, the shellac coating is brought to a proper de ee of softness by the use of the Turkey-re oil, so that a satisfactory stencil can be typed thereon. The original wax sheet 1, 2 may measure about .0025 of an inch in thickness. When the shellac dressing 3 is applied, the gross thickness is increased to about .0027 of an inch.-

In using the new sheet in the typewriter, there may be employed the usual porous backing, 4, behind which may be placed a manila backing sheet 5. The sheet is inserted with the shellac side 3 next to the types. The types penetrate the softened shellac dressing 3 and perforate the wax 2 and deposit the displaced wax on the porous sheet 4. The material of the shellac coating is merely pressed aside locally by the types.

N o preparatory moistening of the sheet is necessary. In a stencil sheet produced according to the foregoing process, the wax coating is little if at all affected by the dressing, and the complete sheet is not only flexible but soft, and the stencil material is easily displaceablc, so that light blows upon the typewriter keys are sufficient to make satisfactory stenclls, thereby substantially reducing the labor of preparing the same.

A sharper stencil character is produced. This is due partly to the hardness of the top surface or dressing which is struck by the types. The objection heretofore met in using wax sheets, that it requires sharp blows upon the typewriter keys to make the stencils sufficiently legible, is overcome.

The protecting top sheet heretofore used for ordinary wax sheets, to prevent filling the types with wax, may be omitted, inasmuch as the new coating does not'come ofl like wax, but is simply pushed aside. The stencil is therefore sharper, partly because of the omission of the top sheet. The dressed wax sheet also affords very fine autographic signatures, using a stylus or the like.

One of the objections to the ordinary wax sheet is that the wax is extremely liable to crack because of its brittleness, and the cracks permit the ink to leak through when the sheet is in the stencil-copying machine, thus producing irregular and unsightly ink marks upon the work-sheets. The sheet prepared according to this invention is quite soft and flexible as compared with previous wax sheets, and may be handled roughly without liability of making cracks therein. The dressing is toughand strong, and does not crack. The wax primary. sheet may crack in handling, but the dressing itself does not crack, and will prevent leakage of ink through the cracks of .the wax sheet. In

other words, the wax in the original sheet can be cracked without cracking the protective softened shellac coating. During the process of making the stencil copies, it often happens that the copy sheets, owing to careless handling, are folded or crumpled up when fed between the rolls of the stencilling machine. Such crumplingcauses injury to or destruction of the ordinary wax stencil, but it has no injurious effect on the present improved stencil sheet, and makes no cracks therein. The wax side of the sheet may even be scratched with a pencil, but no scratch .vill show on the stencil copies.

WVhen the stencil is written, the shellac coating is uppermost. When inserted in the duplicator, the shellac coating of the wax stencil is placed against the cloth ink pad on the cylinder. The ink pad contains more or less knots, ridges or imperfections, which soon perforate an ordinary wax stencil. But they do not perforate the shellac-coated wax stencil. The soft shellac coating is a protection for the wax against the roughnesses of the pad. The shellac coating imparts toughness so that the wax sheet is strengthened against pulling or tearing. It is not so easily stretched or ruptured, and does not yield so readily to the stretching-out tendency which occurs when the sheet is run between the pressure-rolls in the stenciling machine.

- Any dust or grit that imheds itself in the stencil from the ink pad or otherwise, does not work through the shellac coating, as it does through a wax coating. The dust may imbed itself in the improved stencil, but it does not perforate the stencil. It will not work through the shellac coating from either side. Even if it works through the wax, it is stopped by the shellac, and the sheet remains unperforated.

The softened shellac dressing also works as a protective against the softening influence of the ink used in the stencilingmachine. After a weeks exposure, the stencil .sheets do not show softening influence from the ink. while ordinary waxstencils wrinkle and soften in a few days. The rapid destruction of the ordinary wax stencil sheet in. the duplicating machine is believed to be largely due to the action of the ink thereon, the ink tending to soften the wax, and

the pressure of tl1e printing rolls upon the stencil sheet having the effect of producing. pin-holes in the stencil sheet and breaking down the wax where it has been stenciled.

The thin wash or coating of the shellac preparation affords a protection against the disintegrating action of the ink. Since the stencil sheet is placed in the duplicating machine, with the shellac side next to the inking mat, it is believed that the shellac prep.- aration shields the wax from the action of the ink. and also aids to support the pressure of the printing rolls, so that the wax is longer protected from injury, and as many as 1,500 excellent copies can be produced. or five or six times as many as from the ordinary wax sheet. i

The wax coating is less subject to the heat,

having a low melting point. Thestencilcopying operation produces heat, tending to melt away the wax gradually. Shellac has almost ten times the melting point of the wax, so thatthe sheet as a whole 1s not so readily weakened by heat.

The copy-sheets tend to remove the wax on the stencil and rubbing the hand over the newspaper to absorb the ink from the stemcil;

This sheet is not open to the objection of being too-sticky for commercial use, and there is usually no need to pack anything between the sheets.

Heretofore difliculty has been found .in reading typewritten stencils, both when they are in the typewriting machine and also after they are withdrawn therefrom. To overcome this objection it has been the practice, especially in stenciling address cards, to employ an ink-ribbon or anofl'setting carbon-paper between the stencil 'and the platen of the typewriting machine, so that some of theink will offset onto the back of the stencil sheet orcard, and thereby render the same decipherable. One of the objects of the present invention is to produce a stencil sheet in which typed characters shall -be plainly legible Without the necessity of employing inking-ribbon, carbon-shfeet or the like in the typewriting machine.

To "produce legibility of the typewritten stencil'an aniline dye is dissolved into the second of the above-mentioned solutions; or, in other words, the second solution is made b '5 solution of aniline dye in denatured acohol, to which may be added the Turkeyred oil, for the'softening purpose set forth. This dye may be purple, blue, green, or any color; and, when the sheet is floatedin the dyed mixture, the sheet will take on a colored coating of the shellac and sulphonated-castoroil.

When the sheet is stenciled in the typewriting machine or otherwise, the types penetrate the colored varnish 3, disclosmg the underlying whiteportion ofthe stencil sheet, so that the type impressions constitute white characters upon the colored sheet, and contrast clearly and sharply with the violet, blue or other color of the dye, so that the stencil is easily'readable.

The porous sheet 4 forming thebacking of the stencil in the typewriter is usually white, and, because of its contrast with the dye coating, it 'conduces to legibility. v Moreover, the aniline dye has no appreclable efl'ect upon the original wax of the stencil sheet,

the wax retaining its original whiteness, and hence the typed stencil is legible even without the aid of the white backing sheet 4.

- Instead of the floating process for applying the varnish, there may be employed a roller process similar to that which is commonly employed in coating the paper with the original wax. In a roller process, the revolving roller would be partially immersed in the bath of the aforesaid solution of shellac varnish, and this solution will cling to the roller as the latter is re volved. The wax sheet may be drawn over the roller at a speed equaling the surface speed of the roller, and in the same direction, and will receive therefrom a deposit of the coating material or varnish, which may then be dried. i

Variations may be resorted to within the scope of the invention, and portions of the improvementsmay be used without others.

Having thus described my invention, I claim: I

1. A stencil sheet comprising open-mesh tissue paper impregnated or coated with a preparation of parafiim ceresine, lard and japanwax, said coating varnished with shellac which is softened by'Turkey-red oil and dyed in contrast with the color of the wax coating.

2.- A paper sheet coated with wax to which .is applied a dressing or varnish covering the entire surface of the wax and compnsing shellac that is softened, forming an article by typing thereon. I

3. A paper sheet coated with wax to the entire coated surface of which is applied a dressing or varnish comprising shellac that is softened, and a dye of different color from of manufacture for converting into a stencil the wax coating, said sheet forming an article of manufacture for converting into a stencil by typing-thereon.

4. The process of coating a sheet with wax,

' and then coating'the entire exposed surface of the wax on said sheet with shellac dissolved in spirits and softened, preparatory to converting the sheet into a stencil by typing thereon..

5. The-process ofcoating a sheet with wax, and then coating the entire ex osed surface of the wax on said sheet with s ellac dissolved in spirits and softened, said solution of shellac dyed with an aniline dye of different color from the wax coating, preparatorv to converting the sheet into a stencil. by typing thereon.

6. The process of preparing a varnish for wax stencil sheets, of the proportions of 6 pounds of shellac tol gallon of denatured alcohol or spirits, and adding to such preparation "about four volumes, by weight, of

denatured alcohol in 7 which isadissolved a softener for the shellac,

7, The process ofpreparing a varnish for natured alcohol in which is dissolved Turhey-red oil to soften the shellac.

8. The process of preparing a varnish for van stencil sheets, of the proportions of ti pounds of shellac to 1 gallon of denatured alcohol or spirits, and adding to such prepa ration about four volumes, by Weight, of denatured alcohol in which is dissolved 'lurlrey-red oil to soften the shellac, said Eurliey-red oil in the proportion of about 6 per cent by Weight. I

9. The process of preparing a varnish for Wax stencil sheets, of the proportions of 6 pounds of shellac to 1 gallon of denatured alcohol or spirits, and adding to such preparation about four volumes, by Weight, of denatured alcohol in which is dissolved a softener for the shellac, and an aniline dye.

10., The process of preparing a varnish for wax stencil sheets, of the proportions of 6 pounds ofshellacto 1 gallon of denatured alcohol or spirits, and adding to such preparation about four volumes, by Weight, of denatured alcohol in which is dissolved a softener for the shellac, and floating the stencil sheet upon such solution.

- 11.. The process of preparing a varnish for WELX stencil sheets, of the proportions of 6 pounds of shellac to 1 gallon of denatured alcohol or spirits, and adding to such preparation about four volumes, by weight, of denatured alcohol in which is dissolved a softener for the shellac, and fioating the stencil sheet upon such solution, with the Wax-coated side of the stencil sheet down, and then permitting the excess alcohol to evaporate-from the sheet.

12. A Wax-coated stencil sheet to the entire coated surface of which is applied a actress softened and adherent dressing or varnish of manufac sy typing oi shellac, forming an article ture for converting into a st thereon,

13. A bath coating was sheets, CODA prising shel ac varnish, denatured ah lurlrey-red oil aniline it, A friable wax coated the cntii'e'coated surface of u a coating tough flexible material vious to stenciling ink, and comp softened shellac, said sheet forming ar ticle of manufacture for converting into stencil by typing thereon, a so 15. A friable Wax coated stencil sheet to the entire coated surface of which is ap plied a coating of tough flexible material. impervious to stenciling ink, and compris ing softened and dyed shellac, said sheet forming an article of manufacture for con vcrting into a stencil by typing thereon,

16. 'lhe method of protecting a Wax sheet against the softening influence of stenciling ink, comprising varnishing the sheet with softened shellac preparatory to typing the stencil.

1?. The process of thinning a shellac varnish by the use of denatured alcohol spirits to which is added a softener for the shellac, then floating a- Wax coated stencil sheet in said preparation, and permitting the excess alcohol to evaporate from the sheet, prior to converting the sheet into a stencil by typing thereon.

18. The process of thinning a shellac varnish by the use of denatured alcohol spirits in which is dissolved aniline dye, and to which is added a softener for the shellac, then floating a Wax coated stencil sheet in said preparation, the dye being of a color contrasting to the Wax, and permitting the excess alcohol to evaporate from the sheet,

prior to converting the sheet into a stencil by typing thereon. i

srnunr W. FUElt'll-l. 

